We intend to test the hypothesis we formulated based on our previous identification of the ribosome binding sites of mRNAs derived from a plasmid gene and two phage genes related to Gram-positive organisms. For this purpose, we will determine the base sequence of binding sites of mRNAs derived from Gram-positive organisms, with particular interest in obtaining examples related to cellular genes of these organisms. The B. subtilis DNA phage 029 will be used as a model system for studying regulation of early and late gene expression in Gram-positive systems. We will attempt to clone the Clostridium acidi-urici ferredoxin gene in order to be able to study the biosynthesis of this model iron-sulfur protein. We will investigate the domain organization of the trifunctional enzyme, C1-synthase, which contains formyltetrahydrofolate synthetase activity as well as methylene-THF dehydrogenase and methenyl-THF cyclohydrolase acitivity. This will be done through the use of a plasmid that has been constructed containing the yeast gene coding for this protein. We will determine whether C1-synthase is associated in any way with other enzymes involved in one-carbon metabolism, and whether the activities of the eucaryotic enzymes are affected by different factors or in different ways from the equivalent single function proteins that occur in procaryotes.